Just went in to the forums and something redirected me to a Winx screen which is one of those that wants to con you into thinking you have viruses and get you to click an update button that then downloads them.

I have checked my system and it says it was from something on Efestivals, so maybe an advert.

I have no screen shots of the page as I exited it as quick as possible.

EDIT:
This is a screen shot of my browser history showing the pages it went through, hopefully you can find the culprit.